/**
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.hadoop.hdfs.server.protocol;

import java.io.IOException;

import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.hdfs.protocol.HdfsConstants;
import org.apache.hadoop.hdfs.server.common.HdfsServerConstants.NodeType;
import org.apache.hadoop.hdfs.server.common.Storage;
import org.apache.hadoop.hdfs.server.common.StorageInfo;
import org.apache.hadoop.hdfs.server.namenode.NNStorage;
import org.apache.hadoop.util.VersionInfo;

/**
 * NamespaceInfo is returned by the name-node in reply 
 * to a data-node handshake.
 *
 */
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class NamespaceInfo extends StorageInfo {
    // HDFS版本号
    final String buildVersion;
    // 块池id
    String blockPoolID = "";    // id of the block pool
    // 软件本版号`
    String softwareVersion;

    public NamespaceInfo() {
        super(NodeType.NAME_NODE);
        buildVersion = null;
    }

    public NamespaceInfo(int nsID, String clusterID, String bpID,
                         long cT, String buildVersion, String softwareVersion) {
        super(HdfsConstants.NAMENODE_LAYOUT_VERSION, nsID, clusterID, cT,
                NodeType.NAME_NODE);
        blockPoolID = bpID;
        this.buildVersion = buildVersion;
        this.softwareVersion = softwareVersion;
    }

    public NamespaceInfo(int nsID, String clusterID, String bpID,
                         long cT) {
        this(nsID, clusterID, bpID, cT, Storage.getBuildVersion(),
                VersionInfo.getVersion());
    }

    public String getBuildVersion() {
        return buildVersion;
    }

    public String getBlockPoolID() {
        return blockPoolID;
    }

    public String getSoftwareVersion() {
        return softwareVersion;
    }

    @Override
    public String toString() {
        return super.toString() + ";bpid=" + blockPoolID;
    }

    public void validateStorage(NNStorage storage) throws IOException {
        if (layoutVersion != storage.getLayoutVersion() ||
                namespaceID != storage.getNamespaceID() ||
                cTime != storage.cTime ||
                !clusterID.equals(storage.getClusterID()) ||
                !blockPoolID.equals(storage.getBlockPoolID())) {
            throw new IOException("Inconsistent namespace information:\n" +
                    "NamespaceInfo has:\n" +
                    "LV=" + layoutVersion + ";" +
                    "NS=" + namespaceID + ";" +
                    "cTime=" + cTime + ";" +
                    "CID=" + clusterID + ";" +
                    "BPID=" + blockPoolID +
                    ".\nStorage has:\n" +
                    "LV=" + storage.getLayoutVersion() + ";" +
                    "NS=" + storage.getNamespaceID() + ";" +
                    "cTime=" + storage.getCTime() + ";" +
                    "CID=" + storage.getClusterID() + ";" +
                    "BPID=" + storage.getBlockPoolID() + ".");
        }
    }
}
